The preliminary finding of an association of group B streptococcus (GBS) colonization, beta-lactam use during labor and respiratory distress in newborns will be validated in a prospective adequately powered study. The goals of the study are 1) to relate levels of serum bacterial phospholipids to the occurrence of respiratory distress in newborns of mothers colonized by GBS;and 2) to evaluate the effects of beta-lactam use during labor on the release of bacterial phospholipids and thus, the occurrence of respiratory distress in newborns of mothers colonized with GBS. This study will also examine the pathologic effects of [unreadable]asymptomatic[unreadable] GBS colonization and potential adverse effects of beta-lactam use during labor on the newborns. In addition, other potential adverse events or morbidities in mothers and newborns associated with the use of intrapartum antibiotics will be evaluated.